1. Field of the Invention
The present invention relates to a light emitting module and an image surveillance device thereof, and more specifically, to a light emitting module having a lens which has a first biconcave section and a second biconcave section connected to the first biconcave section via a shared section and an image surveillance device thereof.
2. Description of the Prior Art
In general, an image surveillance device usually has light sources disposed therein for providing auxiliary light to capture clear images when the image surveillance device is operated in a dark environment (e.g. in an indoor environment or in the night). A conventional light emitting design is to dispose convex lenses and biconcave lenses in front of the light sources. The biconcave lenses are disposed alternately and aligned with the light sources respectively. In such a manner, after light emitted by the light sources is focused by the convex lenses, the light emitted by the light sources could be diverged by the biconcave lenses so that a light emitting range of the light sources could cover an image capturing range of the lens module.
However, the aforesaid design may cause a dark band problem due to insufficient brightness of a light intersection region of the two adjacent light sources, so as to influence the image capturing quality of the image surveillance device. Furthermore, alternate disposal of the biconcave lenses could occupy much internal space of the image surveillance device and increase the overall volume of the image surveillance device, so as to be disadvantageous to the thinning design of the image surveillance device.